ABSTRACT
OBJECTIVES: Position stability of the abutment should be investigated in four implant systems with a conical implant-abutment connection. MATERIALS AND METHODS: Previously developed formulas and an established experimental setup were used to determine the position stability of the abutment in the four implant systems with a conical implant-abutment connection and different positional index designs: The theoretical rotational freedom was calculated by using the dimensions of one randomly selected implant per system for approximated geometric models. Experimentally, the rotation, the vertical displacement, and canting moments of the abutment after multiple repositioning and hand tightening of the abutment screw were investigated. RESULTS: The experimental rotation and vertical displacement differed between the implant systems tested. The analytical and experimental results for the rotation of the abutment clearly deviated in the three implant systems. CONCLUSIONS: Malpositioning of the abutment was possible in all the implant systems tested. Deviating theoretical and experimental results suggest high manufacturing tolerances during fabrication of the implant components. CLINICAL RELEVANCE: Position stability of the abutment is essential for precisely fitting implant-supported superstructures.
Subject(s)
Dental Abutments , Dental Implant-Abutment Design , Dental Implants , Dental Prosthesis Retention , Dental Stress Analysis , RotationABSTRACT
OBJECTIVE: This retrospective study evaluated the success rate of a fixed retrievable prosthesis based on an electroforming technique combining the advantages of screw- and cement-retained principles. METHOD AND MATERIALS: Forty patients (17 men and 23 women) with a mean age of 62.2 years were treated. A total of 353 implants were placed in the edentulous maxilla, mandible, or both jaws to allow prosthetic rehabilitations with 55 fixed prostheses. Clinical success of the implants was based on the criteria of Buser. Technical complications monitored throughout the wearing period are described. Retrievability of the restoration with a conventional crown remover was checked at 6, 12, and 36 months. The cumulative survival rate of the implants was measured. RESULTS: After a mean observation period of 4.08 years (range 22 to 62 months), a cumulative survival rate of 99.15% was recorded for the 234 maxillary implants (234 Camlog RootLine, Camlog) and for the 119 mandibular implants (72 Camlog RootLine, 47 Camlog ScrewLine). Three implants failed before prosthetic loading. Monitored technical complications were seen in 10.91% of the restorations; they comprised ceramic chip-off and relining. CONCLUSIONS: This fixed implant-retained prosthesis based on electroforming indicates a comparable clinical efficacy to other techniques and allows scheduled retrieval.
Subject(s)
Dental Prosthesis, Implant-Supported , Denture Design , Jaw, Edentulous/rehabilitation , Aged , Aged, 80 and over , Dental Abutments , Dental Implants , Dental Porcelain , Dental Prosthesis Design , Dental Restoration Failure , Denture Rebasing , Denture Retention/instrumentation , Electrochemical Techniques , Female , Follow-Up Studies , Humans , Jaw, Edentulous/surgery , Male , Mandible/surgery , Maxilla/surgery , Middle Aged , Retrospective Studies , Survival Analysis , Treatment OutcomeABSTRACT
PURPOSE: The purpose of this study was to evaluate rotational, vertical, and canting changes in the position of the rotation-safe component in the implant-abutment assemblies of five different implant systems (ITI, Steri-Oss, Camlog, Astra Tech, and Replace Select) after manual removal and reassembly. MATERIALS AND METHODS: Prefabricated stainless steel models were used for each implant system, into which six implants were fixated with polymethylmethacrylate resin. Rotation-safe abutments (components) were screwed into the implants according to the manufacturers' specifications. Three test persons with varying knowledge of the theory and practice of implant dentistry manually assembled and reassembled the implant-abutment joint using each system-specific screwdriver 20 times each. A coordinate reading machine was used to detect discrepancies in position after each reassembly in relation to a coordinate system. Rotational freedom, changes in vertical height, and deviations in angulation were assessed. Statistical analysis was performed based on the nonparametric analysis of variance of repeated measurements. RESULTS: The tested complexes showed rotational freedom that ranged from 0.92 to 4.92 degrees, with significant differences between the systems. Camlog was significantly different from all other systems tested regarding rotational freedom, whereas Steri-Oss, Astra Tech, and Replace Select showed no significant difference between each other because of their nondiscrepant mean degree of rotational freedom. Vertical alterations in position ranged from 1 to 83 microm. A statistically significant difference was detected between butt-joint and beveled implant-abutment connections, with ITI and Astra Tech showing no significant difference when compared to each other, but displaying a significant difference versus all other systems tested. Canting discrepancies were not significant, with no influence of implant system or test person clearly detectable. CONCLUSION: Three-dimensional changes in the location of the abutment in relation to the implant result after manual assembly and reassembly of the implant-abutment complex.
Subject(s)
Dental Abutments , Dental Implants , Analysis of Variance , Dental Prosthesis Design , Dental Stress Analysis , Rotation , Stress, MechanicalABSTRACT
This article describes a method of fabricating a fixed retrievable implant-retained prosthesis based on electroforming. This method combines the advantages of both the cement- and screw-retained prostheses, including passive fit, ease of fabrication, and retrievability. The absence of visible occlusal screw-canals adds to its increased esthetic appeal.
